| The Bacillus amyloliquefaciens strain AiL3 was early screened as a stong antagonistic bacteria against the Colletotrichum gloeosporioides. In order to study the efficacy of strain AiL3 on control of the pre-and post-harvest mango anthracnose disease caused by C. gloe- osporioides, the biocontorl efficacy of the strain and its cellular exudates were tested in this paper. In addition, the taxonomic position, antifungal substances and biocontrol efficacy of the marine bacterial strain Kc-38 which was isolated from mangroves and had strong inhibitory activity against C. gloeosporioides were also studied in the paper.The result of using the strain AiL3 and its cellular exudates to control mango anthracnose disease in the fields showed that: the bacterial suspension and its cellular exudates had 6.83% and 15.87% control effect on the mango foliar anthracnose disease at 45d respectively after spraying three times every 15ds during mango budding and fruiting stages, and the control efficacy of 10-fold diluent mixed with 0.1%Tween-80 were 18.58% and 47.54% respectively. The control efficacy of the bacterial suspension and its cellular exudates to the mango furit anthracnose disease were 28.96% and 28.52% respectively, and the control efficacy of 10-fold diluent mixed with 0.1%Tween-80 were 43.86% and 49.70% respectively. And the 10-fold diluent of the bacterial cellular exudates mixed with 0.1%Tween-80 had the same contorl efficacy as the 45% Prochloraz diluted 500 times.The result of using the strain AiL3 and its cellular exudates to control postharvest mango anthracnose disease showed that: soaking the mango fruits with the bacterial suspension and its cellular exudates for 10 min without inoculated the pathogen C. gloeosporioides, their contorl efficacy were 66.67% and 65.55% at 9d, and 28.26% and 31.06% at 12d respectively. While the 45% Prochloraz diluted 500 times had better contorl efficacy of 85.19% and 57.61% at 9d and 12d respectively than the bacterial suspension and its cellular exudates, and there were marked differences among them.Bagged postharvest mango fruits were inoculated the pathogen C. gloeosporioides and then soaked with the bacterial suspension and its cellular exudates for 10 min 24h and 48h after inoculation respectively. The result showed that: the control efficacy of the bacterial suspension were 46.31%, 43.24% and 17.19%,20.00% at 6d and 9d respectively, and the control efficacy of its cellular exudates were 49.47%, 29.73% and 32.80%, 13.89% at 6d and 9d respectively. Their control efficacy to post-harvest mango anthracnose disease were both better than 45% Prochloraz diluted 500 times which had the control efficacy of 36.85%, 27.03% and 17.31%, 9.88% at 6d and 9d respectively. The results showed that good biocontrol efficacy was achieved. It indicated that AiL3 was a good candidate strain to biological control the mango anthracnose disease, and had a good prospect of development and utilization.The endophytic bacterial strain Kc-38 isolated from the tissue of Kandelia candel had strong inhibitory activity against many plant pathogenic fungi, such as Colletotrichum gloeosporioides, Fusarium oxysporum, and so on. According to the morphological, physiological and biochemical characteristics, and 16S rDNA sequence analysis, strain Kc-38 was identified as Bacillus amyloliquefaciens. The strain Kc-38 had good control efficacy on mango anthracnose disease caused by C. gloeosporioides. When tested on postharvest mango fruits and treated with the bacterial suspension and its cellular exudates, the control efficacy on the 9th d reached 65.12% and 62.79%, respectively. Further studies showed that the antibiotic substances produced by the strain were some kind of antifungal proteins. The proteins were found to be UV-tolerant and thermostable. |
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